Mazda Miata MX-5 Engine Service manual
Below you will find brief information for Engine Miata MX-5. This service manual covers engine identification, removal and installation, adjustment, overhaul, engine lubrication, oil pump, torque specifications and engine specifications. This document will help you diagnose and repair your engine.
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1994 ENGINES 1.8L 4-Cylinder
1994 ENGINES
1.8L 4-Cylinder
ENGINE IDENTIFICATION
NOTE: For repair procedures not covered in this article, see ENGINE OVERHAUL
PROCEDURES - GENERAL INFORMATION article in the GENERAL
INFORMATION section.
Engineering codes can identify basic engine type. See ENGINE IDENTIFICATION CODE table. Engines can be further identified by engine number.
On Miata, engine number is stamped on flange, at upper right rear of cylinder block deck as viewed from flywheel.
ENGINE IDENTIFICATION CODE
Application
Miata DOHC
Code
BP
ADJUSTMENTS
VALVE CLEARANCE ADJUSTMENT
NOTE: Valve clearance is not adjustable. Some Hydraulic Lash Adjuster (HLA) noise may occur during engine start-up. Noise should disappear after engine reaches normal operating temperature. If noise persists, change engine oil. If oil change does not reduce noise, check with manufacturer for modified HLA.
REMOVAL & INSTALLATION
NOTE: For reassembly reference, label all electrical connectors, vacuum hoses and fuel lines before removal. Also place mating marks on engine hood and other major assemblies before removal.
FUEL PRESSURE RELEASE
Disconnect fuel pump relay, located behind dash, left of steering column. Start engine and allow to idle until it stalls. Turn ignition off. Disconnect negative battery cable, and reconnect circuit opening relay. When disconnecting fuel hoses, cover connection with shop rag to catch fuel spray.
ENGINE
NOTE: On models with audio anti-theft system, radio will not operate if power to radio
1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
is cut. Obtain code from customer to reactivate radio. To reactivate radio after reconnecting power supply, turn ignition switch to ACC position. press and hold FF and REW buttons until "cod e" is displayed. Again press and hold FF and REW buttons until bars (--- -) are displayed. Use preset button No. 1 to enter first number, No. 2 to enter second number, 3 for third number, etc. Press FF and REW buttons for about 2 seconds until a beep is heard. After 5 seconds, flashing "cod e" will go away and radio will operate.
Removal
1. Relieve fuel pressure. See FUEL PRESSURE RELEASE . Disconnect negative battery cable from trunk-mounted battery. Reference mark hood and remove. Raise vehicle, and remove engine undercover.
See Fig. 1 . Drain engine oil, transmission oil and cooling system.
2. Remove transmission. For automatic or manual transmission removal procedure, see appropriate
TRANSMISSION REMOVAL & INSTALLATION article in the TRANSMISSION/TRANSAXLE section.
3. Remove all cooling system hoses and A/T oil cooler lines at radiator (if equipped). Remove radiator and cooling fans as an assembly. Remove all drive belts. DO NOT disconnect power steering hoses or A/C compressor hoses. Remove power steering pump and A/C compressor from engine, and secure units away from engine.
4. Remove air cleaner assembly and throttle body intake duct assembly. See Fig. 2 . Remove throttle cable.
Note locations and disconnect all necessary electrical connectors, ground wires, vacuum hoses, fuel hoses, coolant hoses and control cables for engine removal. Plug all fuel hoses to prevent leakage.
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Fig. 1: Removing & Installing Drive Train Components
Courtesy of MAZDA MOTORS CORP.
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Fig. 2: Removing Engine Components
Courtesy of MAZDA MOTORS CORP.
NOTE: Proper installation of PPF is critical for aligning drive shaft and eliminating harmonic vibrations.
Installation
1. To install, reverse removal procedure. After installing engine mount nuts, mount PPF to transmission, and tighten long bolts by hand. Ensure bolt sleeve and PPF/differential mounting spacer are installed to differential housing block.
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
2. Tighten PPF/differential mounting spacer bolts to 27-38 ft. lbs. (37-52 N.m). See Fig. 3 . Install PPF to differential. Hand-tighten long bolts. Ensure PPF-to-differential large shank reamer bolt and spacer are properly installed.
NOTE: Reamer bolt is the front long bolt attaching PPF to differential. This bolt aligns PPF with drive train.
3. When PPF is properly aligned between transmission and differential, tighten all long mounting bolts to specification. Install rear transmission-to-PPF bracket, and tighten to specification. See TORQUE
SPECIFICATIONS . To complete installation, reverse removal procedure. Before installing M/T shift lever, add gear oil to transmission through shifter hole. Fill all fluids to correct level.
Fig. 3: Locating PPF-To-Differential Reamer Bolt, Sleeve & Spacer
Courtesy of MAZDA MOTORS CORP.
INTAKE MANIFOLD
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Removal
1. Relieve fuel pressure. See FUEL PRESSURE RELEASE . Disconnect negative battery cable. Drain cooling system. Remove air cleaner assembly and ducting. See Fig. 2 . Mark and disconnect coolant hoses, vacuum hoses and electrical connectors from intake manifolds.
2. Disconnect throttle cable. Remove fuel lines from fuel rail and pressure regulator. Remove throttle body intake duct housing and throttle body. Remove air valve.
3. Remove intake manifold support bracket from underneath manifold. Disconnect injector harness connectors, and remove injectors/fuel rail assembly. Remove intake manifold and gasket.
Installation
1. Ensure all gasket surfaces are clean and flat. Install new gasket and intake manifold to cylinder head.
Tighten manifold bolts/nuts evenly to specification, starting from center bolt and alternating outward. See
TORQUE SPECIFICATIONS . Install support bracket underneath intake manifold.
2. Install gasket and upper intake manifold (if equipped). Tighten bolts/nuts evenly to specification, alternating from top to bottom.
3. To complete installation, reverse removal procedure. Ensure throttle cable has .04-.12" (1-3 mm) free play. Ensure injectors twist freely and are not cocked in insulator "O" rings. Refill engine with coolant.
EXHAUST MANIFOLD
Removal & Installation
1. Disconnect oxygen sensor. Remove heat shields. Disconnect downpipe from exhaust manifold. Remove exhaust manifold.
2. To install, reverse removal procedure. Ensure all mating surfaces are clean and flat. Install new gasket to cylinder head. Tighten manifold bolts evenly to specification, starting from center bolt and alternating outward. See
TORQUE SPECIFICATIONS
.
CYLINDER HEAD
Removal
1. Drain engine coolant. Release fuel pressure. See FUEL PRESSURE RELEASE . Note locations and disconnect all necessary electrical connectors, ground wires, vacuum hoses, fuel hoses, coolant hoses and control cables for cylinder head removal. Plug all fuel hoses to avoid leakage.
2. Remove spark plug wires from spark plugs. Remove all drive belts. Remove water pump pulley. Remove timing belt. See TIMING BELT . Remove camshaft/rocker cover.
3. Remove front exhaust pipe. Remove intake manifold support bracket. Loosen all cylinder head bolts evenly, in 3 steps, in reverse of tightening sequence. See Fig. 4 . Remove bolts and cylinder head assembly.
Inspection
Carefully clean carbon and gasket material from all mating surfaces. Clean threads of cylinder head bolts. Use a
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder tap to clean threads in engine block. Check cylinder head for warpage. Resurface or replace head if it is not within specification. Check valve train components. Replace or resurface components if they are not within specification. See CYLINDER HEAD and VALVES & VALVE SPRINGS tables under ENGINE
SPECIFICATIONS.
Installation
Install cylinder head gasket, cylinder head assembly and bolts. Tighten cylinder head bolts in 2 steps and in sequence to specification. See Fig. 4 . See TORQUE SPECIFICATIONS . To complete installation, reverse removal procedure.
Fig. 4: Cylinder Head Bolt Tightening Sequence
Courtesy of MAZDA MOTORS CORP.
CRANKSHAFT FRONT SEAL
Removal
Disconnect negative battery cable. Remove drive belts and crankshaft pulley. Remove water pump pulley,
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder timing belt covers and timing belt. See TIMING BELT . Use Crankshaft Lock Tools (49-S120-710 and 49-
B011-102) to lock crankshaft sprocket into position. Remove crankshaft sprocket bolt. Remove crankshaft sprocket using steering wheel puller. Pry out seal.
Installation
1. Apply light oil coat to seal lip. Using a hammer and seal installer, tap seal into oil pump body until it is flush with edge of pump body. DO NOT bottom seal in pump body. Align keyway slots, and install crankshaft sprocket and Woodruff key with tapered side toward oil pump body. Install crankshaft sprocket bolt.
2. Using Crankshaft Lock Tools (49-S120-710 and 49-B011-102), lock crankshaft sprocket into position.
Tighten lock bolt to specification. See TORQUE SPECIFICATIONS .
3. Install timing belt. See TIMING BELT under REMOVAL & INSTALLATION. Install timing belt covers, pulleys and drive belts. Reconnect negative battery cable, and ensure timing is correct.
TIMING BELT
NOTE: For 1994 vehicles, the manufacturer recommends the belt be replaced at 60,000 mile intervals for vehicles sold outside of California. For vehicles sold in
California, inspect timing belt at 60,000 and 90,000 miles, and replace timing belt at 105,000 miles. For removal and installation procedure, see TIMING BELT
REPLACEMENT - 1.8L - DOHC, BP ENG .
HYDRAULIC LASH ADJUSTER (HLA)
NOTE: If hydraulic lash adjusters are persistently noisy, check with manufacturer for availability of modified adjusters.
Removal
Disconnect negative battery cable. Remove camshaft. See CAMSHAFT . Mark location of each HLA for reassembly reference. Remove HLA from cylinder head.
Inspection
Place HLA in palm of hand. Attempt to compress HLA plunger with thumb. If plunger compresses, replace
HLA.
Installation
Insert HLA in original location. To complete installation, reverse removal procedure. Tighten camshaft caps evenly in sequence to specification. See Fig. 5 . See TORQUE SPECIFICATIONS .
CAMSHAFT
NOTE:
Microsoft
Intake camshaft has slot for crank angle sensor drive. Match mark camshafts
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1994 ENGINES 1.8L 4-Cylinder
and sprockets for installation reference.
Removal
Remove cylinder head cover. Remove timing belt. See TIMING BELT . Remove distributor/crank angle sensor. Reference mark camshafts, caps and sprockets, and remove sprockets. Loosen camshaft cap bolts evenly in 2-3 steps, in sequence. See Fig. 5 . Remove camshafts.
Inspection
Check camshaft end play. Check camshaft journal diameters and bearing clearances. Check camshaft lobes for wear. See CAMSHAFT table under ENGINE SPECIFICATIONS. If any measurement is not within specification, replace camshaft and/or cylinder head.
Installation
To install, reverse removal procedure. On both camshafts, apply small amount of silicone sealant to contact area of cylinder head/camshaft seal cover cap. Tighten camshaft caps evenly in sequence to specification. See Fig.
5 . See TORQUE SPECIFICATIONS .
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Fig. 5: Camshaft Cap Bolt Removal & Installation Sequence
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Courtesy of MAZDA MOTORS CORP.
CRANKSHAFT REAR OIL SEAL
Removal & Installation
1. Disconnect negative battery cable. Remove transmission/transaxle and flywheel. For automatic or manual transmission removal procedure, see appropriate TRANSMISSION REMOVAL & INSTALLATION article in the TRANSMISSION/TRANSAXLE section. Pry out rear oil seal.
2. To install, apply light coat of oil to seal lip and push seal over crankshaft. Tap seal into rear cover until it is flush with edge of rear cover. DO NOT bottom seal in cover.
3. Completely remove used sealant from flywheel bolts. Apply lock-type sealant to bolts, and install flywheel to crankshaft. Tighten bolts to 71-76 ft. lbs. (96-103 N.m) in a star-pattern sequence. Install clutch assembly (if equipped), and tighten cover bolts to 13-20 ft. lbs. (18-26 N.m) in a star-pattern sequence. Install transmission. For automatic or manual transmission removal procedure, see appropriate
TRANSMISSION REMOVAL & INSTALLATION article in the TRANSMISSION/TRANSAXLE section (See above).
WATER PUMP
Removal & Installation
1. Drain engine coolant. Disconnect battery cable. Position No. 1 cylinder at TDC of compression stroke.
2. Remove air cleaner intake duct between throttle body and air cleaner/filter assembly. Remove upper radiator hose and by-pass hoses from thermostat housing.
3. Remove drive belts and water pump pulley. Remove power steering pump with hoses attached, and secure pump away from engine (if necessary). Remove timing belt, tensioner and idler. See TIMING
BELT .
4. Unbolt water inlet pipe from water pump. Water pump inlet pipe has lower radiator hose and by-pass pipe attached to it. Remove bolts from water pump. To install, reverse removal procedure. Tighten bolt to specification. See
TORQUE SPECIFICATIONS
.
NOTE: For further information on cooling systems, see COOLING SYSTEM
SPECIFICATIONS & DRIVE BELT ROUTING article and/or ENGINE COOLING
FAN article.
OIL PAN
NOTE: Engine must be supported in order to remove oil pan.
Removal & Installation
1. Disconnect negative battery cable. Remove dipstick, tube and "O" ring. Raise vehicle on hoist. Remove engine undercover. Drain engine oil. Disconnect steering column shaft at steering rack coupling. Remove engine mount nuts. See Fig. 6 . Lift and support engine using jack.
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
2. Support crossmember using transmission jack, and remove crossmember bolts. Slowly and carefully lower crossmember until clearance between oil pan and steering rack is about 4 inches. Remove oil pan bolts from engine block and transmission.
3. DO NOT damage sealant contact surfaces. Remove oil pan by prying between oil pan and transmission support. Remove oil pan baffle by prying it from engine. See Fig. 6 . DO NOT deform oil pan baffle.
Replace oil pan baffle if deformed. Clean sealant from oil pan, bolts, engine block and both sides of oil pan baffle.
4. To install, apply oil resistant sealant to engine block and oil pan. Install oil pan baffle and oil pan. To complete installation, reverse removal procedure. Tighten bolts to specification. See TORQUE
SPECIFICATIONS . Fill engine with oil to specification. See ENGINE LUBRICATION SYSTEM under ENGINE OILING.
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Fig. 6: Removing Crossmember & Oil Pan
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Courtesy of MAZDA MOTORS CORP.
OVERHAUL
CYLINDER HEAD
Cylinder Head
Clean carbon and gasket material from all mating surfaces. Using a tap, clean cylinder head threads. Check cylinder head for warpage, and resurface or replace if warpage exceeds specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS.
Valve Springs
Ensure valve spring free length, out-of-square and pressure are within specification. See VALVES & VALVE
SPRINGS table under ENGINE SPECIFICATIONS. Replace valve spring if necessary.
NOTE: Intake and exhaust valve stem seals are different. Exhaust seals can be identified by ridges molded into top of seal. Intake seals do not have identifying ridges. Incorrect installation of valve stem seals will cause premature failure.
Valve Stem Oil Seals
Use Installer Set (49-L012-0A0) to install valve seals. See Fig. 7 . Adjust installer dimension "L" to seal depth of .720-.744" (18.3-18.9 mm). Using hand pressure ONLY, install seal until it contacts cylinder head. Lightly oil valve seal lip.
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Fig. 7: Installing Valve Guide Seals
Courtesy of MAZDA MOTORS CORP.
NOTE: Use only new exhaust valve guides to replace intake or exhaust valve guides.
Valve Guides
1. Check valve stem-to-valve guide oil clearance. Ensure valve guide inside diameter is within specification.
See CYLINDER HEAD table under ENGINE SPECIFICATIONS.
2. Completely disassemble cylinder head. Gradually heat cylinder head in water to 194°F (94°C). Using
Valve Guide Remover (49-B002-005), drive valve guide out, working from combustion chamber side of cylinder head. Repeat procedure if required, keeping cylinder head hot so aluminum head will not warp.
3. If required, install new circlip on guide. Using proper components of Valve Guide Installer (49-L012-
0A0), adjust installer guide depth (dimension "L") to specification using depth micrometer or caliper. See
VALVE GUIDE INSTALLED HEIGHT table. See Fig. 8 .
4. Insert guide into pre-adjusted installer, and drive guide into cylinder head from camshaft side until guide circlip and/or installer contact cylinder head. Measure dimension "L" (guide installed height). See Fig. 8 or Fig. 9 . If installed height is not within specification, adjust or replace valve guide or cylinder head as necessary.
VALVE GUIDE INSTALLED HEIGHT
Application
Miata
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In. (mm)
.720-.744 (18.30-18.90)
© 2005 Mitchell Repair Information Company, LLC.
1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Fig. 8: Adjusting Valve Guide Installer & Installing Guide
Courtesy of MAZDA MOTORS CORP.
Fig. 9: Measuring Installed Valve & Guide Height
Courtesy of MAZDA MOTORS CORP.
Valve Seat
1. Service valve guide before valve seat. Valve seat replacement information is not available from manufacturer. Inspect valve seat for roughness and damage. Check valve seat angle and seat width.
2. Measure seat contact width on valve, and ensure seat contact position is in center of valve face. Service
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder seat if angle and width are not within specification. See CYLINDER HEAD table under ENGINE
SPECIFICATIONS. Measure valve installed height after servicing valve seat. See Fig. 9 . See VALVE
INSTALLED HEIGHT table.
3. If valve installed height is within serviceable range, install adjusting shim on spring seat. If installed height exceeds serviceable range, replace cylinder head.
VALVE INSTALLED HEIGHT
Application
Normal
Serviceable
In. (mm)
1.772-1.791 (45.00-45.50)
1.733-1.772 (45.60-46.50)
Valves
Check valve face angle, head diameter, margin thickness and stem diameter. Service or replace valves if measurements are not within specifications. See VALVES & VALVE SPRINGS table under ENGINE
SPECIFICATIONS.
Valve Seat Correction Angles
Measure seat contact width on valve. See VALVE SEAT . Ensure valve/seat contact position is at center of valve face. If seat contact is too wide or too high, correct it using a 70-degree cutter.
VALVE TRAIN
Hydraulic Lash Adjusters
1. Remove camshaft cover. Check movement of each Hydraulic Lash Adjuster (HLA) by pushing downward using hand pressure only. If HLA compresses, replace HLA. To remove HLA, remove camshafts. See CAMSHAFT under REMOVAL & INSTALLATION. Mark location of HLA before removing it from bore. Lift HLA from cylinder head.
NOTE: If hydraulic lash adjusters are persistently noisy, check with manufacturer for availability of modified adjusters.
2. Inspect HLA friction surfaces for wear and damage. Replace HLA if required. Coat HLA with engine oil, and install it in original location. Ensure HLA moves smoothly in bore by using small magnet attached to
HLA.
CYLINDER BLOCK ASSEMBLY
NOTE: During disassembly, match mark components for reassembly reference.
Piston & Connecting Rod Assembly
1. Before removing rod cap from crankshaft, measure and record rod side play. See CONNECTING RODS table under ENGINE SPECIFICATIONS.
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
2. Remove rod cap from crankshaft. Install short pieces of rubber hose over rod bolts. Push piston and rod assembly out of block.
3. To install, ensure parts are matched to cylinder. Ensure piston, rod, rings and bearings are properly fitted and in related positions. See Fig. 10 . Install piston and rod assembly into block.
Fig. 10: Assembling Piston, Rod & Rings
Courtesy of MAZDA MOTORS CORP.
Piston Pin Replacement
Match mark piston-to-pin and rod-to-piston positions for proper reassembly. Remove piston pin retaining clip.
Drive piston pin out of piston and rod assembly. To install, insert one piston pin retaining clip into groove in piston. Ensure piston is positioned properly on connecting rod. See Fig. 10 . Tap piston pin into piston and through rod. Install second retaining clip. Piston should pivot freely.
Fitting Pistons
1. Ensure pistons are not scored or damaged. Measure piston diameter on piston skirt, at 90-degree angle from piston pin, .65" (16.5 mm) below lowest ring groove. See PISTONS, PINS & RINGS table under
ENGINE SPECIFICATIONS.
2. Check piston-to-cylinder wall clearance in 3 different vertical places of piston travel. If clearance is not within specification, re-bore cylinders to fit oversize pistons. Using NEW piston rings, measure piston ring side clearance around entire piston circumference. If clearance is not within specification, replace piston.
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
NOTE: Pistons and rings are available in .010" (.25 mm) and .020" (.50 mm) oversize.
Piston Rings
Insert NEW piston ring into cylinder, and measure ring end gap. Grind ring ends or replace piston ring if ring end gap is not within specification. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS.
Crankshaft & Main Bearings
1. Check crankshaft connecting rod journals for wear, out-of-round, taper and undersize. Machine or replace crankshaft and/or bearings as necessary. See CRANKSHAFT, MAIN & CONNECTING ROD
BEARINGS table under ENGINE SPECIFICATIONS.
2. Before removing main cap, measure and record crankshaft end play by prying crankshaft forward then rearward. Using Plastigage method, measure and record main bearing oil clearance. Remove crankshaft.
Measure and record each main journal diameter in 2 places.
3. Main bearing caps are marked and must be installed in original position. Tighten bearing caps evenly to specification. See TORQUE SPECIFICATIONS .
Thrust Bearing
Install thrust bearing before installing crankshaft. Check crankshaft end play with crankshaft bearings and caps installed, but without connecting rods attached to crankshaft. DO NOT turn crankshaft until bearings are lubricated. Replace thrust bearing if end play is not within specification. See CRANKSHAFT, MAIN &
CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS. Oversize thrust bearings are available.
Cylinder Block
Check cylinder bore out-of-round, taper, ridge and piston-to-cylinder bore clearance. Check head gasket surface for warpage. If warpage is not within specification, machine or replace cylinder block as necessary. See
CYLINDER BLOCK table under ENGINE SPECIFICATIONS. Remove, clean and install oil jets for piston oil spraying.
ENGINE OILING
ENGINE LUBRICATION SYSTEM
NOTE: For cross-sectional view of engine oil circuit, See Fig. 11 .
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Fig. 11: Cross-Sectional View Of Engine Oil Circuit
Courtesy of MAZDA MOTORS CORP.
Crankcase Capacity
See ENGINE OIL CRANKCASE CAPACITY table.
Oil Pressure
With engine at operating temperature, oil pressure should be 28-43 psi (2.0-3.0 kg/cm
2
) at 1000 RPM, and 43-
57 psi(3.0-4.0 kg/cm
2
) at 3000 RPM.
Oil Pressure Relief Valve
Pressure relief valve opening pressure is 50-64 psi (3.5-4.5 kg/cm
2 body and is not adjustable.
). Pressure relief valve is located in oil pump
ENGINE OIL CRANKCASE CAPACITY
Application
Without Filter
With Filter
Qts. (L)
3.8 (3.8)
4.0 (3.8)
OIL PUMP
Removal & Installation
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
1. Disconnect negative battery cable. Remove dipstick, tube and "O" ring. Drain engine oil and coolant.
Remove drive belts, crankshaft and water pump pulleys. Remove alternator, A/C compressor and mounting bracket. Without disconnecting A/C hoses, secure A/C compressor away from engine. Remove timing belt and related components. See TIMING BELT under REMOVAL & INSTALLATION.
2. Hold crankshaft sprocket in place, and remove crankshaft sprocket bolt. Remove crankshaft sprocket using steering wheel puller. Leave crankshaft Woodruff key in place.
3. Remove oil pan and oil pump pick-up tube. See OIL PAN under REMOVAL & INSTALLATION.
Remove oil pump housing assembly. See Fig. 12 . Carefully clean all gaskets and sealant from mating surfaces without damaging sealing/mating surfaces. Remove all sealant from components and bolts.
Check oil pump clearances. Repair or replace pump if necessary. See OIL PUMP SPECIFICATIONS table.
4. To install, reverse removal procedure. Tighten all bolts to specifications. See TORQUE
SPECIFICATIONS .
OIL PUMP SPECIFICATIONS
Application
Inner Gear Tip-To-Outer Gear Clearance
Outer Gear-To-Pump Body Clearance
Gear End Play-To-Pump Body Clearance
Pressure Spring Length
Maximum Clearance In. (mm)
.0079 (.201)
.0079 (.201)
.0055 (.140)
1.809 (45.94)
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1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Fig. 12: Exploded View Of Oil Pump
Courtesy of MAZDA MOTORS CORP.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS
Application
Alternator Top Bolt
Camshaft Sprocket Bolt
Compressor Bracket-To-Engine Bolt
Connecting Rod Cap Nut
Crankshaft Pulley Attaching Bolts
Crankshaft/Timing Belt Sprocket Bolt
Crossmember-To-Frame Bolt
Cylinder Head Bolt
(2)
Step 1
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Ft. Lbs. (N.m)
27-38 (37-52)
36-45 (49-61)
28-38 (38-51)
35-37 (48-50)
9-13 (12-18)
116-123 (157-167)
47-66 (63-89)
Page 22
35-40 (47-54)
© 2005 Mitchell Repair Information Company, LLC.
1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Step 2 (Final)
Distributor Bolt
Drive Shaft Bolts
Engine Mount-To-Frame Nut
Exhaust Header Pipe-To-Exhaust Manifold Nut
Exhaust Manifold Nut
Flywheel Bolt
Fuel Rail Bolt
Intake Manifold Bolt/Nut
Intake Manifold Support Bracket
Main Bearing Cap Bolt
Step 1
Step 2 (Final)
Motor Mount Nut
Motor Mount-To-Engine Bolt
Oil Pan Support-To-Transaxle
Oil Pump-To-Block Bolt
PPF/Differential Spacer Mounting Bolt
(2)
PPF-To-Differential Long Mounting Bolt
(2)
PPF-To-Transmission Side Mounting Bolt
(2)
PPF/Transmission Rear Bracket Mounting Bolt
Spark Plug
Timing Belt Tensioner Bolt
Water Pump Bolt
Camshaft Cap Bolt
Camshaft/Rocker Cover Bolt
Crankshaft Pulley Bolts
Oil Jet
Oil Pan Bolt
Oil Strainer Bolt
Water Pump Pulley Bolt
(1)
Tighten evenly to specification in alternating sequence.
(2) Tighten in sequence. See Fig. 4 .
(3) Tighten in sequence. See Fig. 5 .
ENGINE SPECIFICATIONS
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56-60 (76-81)
14-19 (19-26)
20-22 (27-30)
42-57 (57-77)
23-34 (31-46)
(1)
28-34 (38-46)
71-76 (96-103)
14-19 (19-26)
(1)
14-19 (19-26)
14-19 (19-26)
(1)
22-27 (30-37)
(1)
40-43 (54-58)
42-58 (57-79)
27-40 (37-54)
28-38 (38-52)
14-19 (19-26)
27-38 (37-52)
77-91 (104-123)
77-91 (104-123)
27-40 (37-54)
11-17 (15-23)
27-38 (37-52)
14-19 (19-26)
INCH Lbs. (N.m)
(3)
100-125 (11.3-14.1)
43-78 (5-9)
109-152 (12-17)
104-156 (12-18)
69-95 (8-11)
69-95 (8-11)
69-95 (8-11)
1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
GENERAL SPECIFICATIONS
Application
Displacement
Bore
Stroke
Compression Ratio
Fuel System
Horsepower @ RPM
Torque Ft. Lbs. @ RPM
Specification In. (mm)
112.2 Cu. In.
3.27" (83.0)
3.35" (85.0)
9.0:1
PFI
128 @ 6500
110 @ 5000
CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS
Application
Crankshaft
End Play
Standard
Maximum
Maximum Runout
Main Journals
Diameter
Out-Of-Round & Taper
Oil Clearance
Standard
Maximum Wear Limit
Crankpin Journal
Diameter
Out-Of-Round & Taper
Oil Clearance
Standard
Maximum Wear Limit
CONNECTING RODS
Application
Bore Diameter
Crankpin Bore
Pin Bushing Bore
Center-To-Center Length
Maximum Bend
Side Play
Standard
Wear Limit
Microsoft
Sunday, July 05, 2009 1:23:06 PM Page 24
In. (mm)
.0031-.0111 (.079-.282)
.012 (.30)
.0016 (.040)
1.9660-1.9668 (49.938-49.956)
.002 (.05)
.0007-.0014 (.018-.036)
.0039 (.100)
1.7693-1.7699 (44.940-44.956)
.002 (.05)
.0008-.0027 (.017-.068)
.0039 (.100)
In. (mm)
1.8898-1.8904 (48.000-
48.016)
.7875-.7880 (20.003-20.014)
5.230-5.234 (132.85-132.95)
.003 (.08)
.0043-.0103 (.110-.262)
.012 (.30)
© 2005 Mitchell Repair Information Company, LLC.
PISTONS, PINS & RINGS
Application
Pistons
Clearance
Standard
Maximum
Diameter
Standard
Pins
Diameter
Piston Fit
Rings
End Gap
No. 1
Standard
Wear Limit
No. 2
Standard
Wear Limit
Oil Ring
Standard
Wear Limit
Side Clearance
Standard
Wear Limit
CYLINDER BLOCK
Application
Cylinder Bore
Standard Diameter
Maximum Taper & Out-Of-Round
Deck Height
Standard
Minimum
Maximum Deck Warpage
CYLINDER HEAD
Application
Cylinder Head Height
Maximum Warpage
Microsoft
Sunday, July 05, 2009 1:23:06 PM
1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
In. (mm)
.0013-.0023 (.032-.059)
.006 (.15)
3.2659-3.2667 (82.954-82.974)
.7869-.7871 (19.987-19.993)
-.0002-.0005 (-.005-.013)
.006-.012 (.15-.30)
.039 (1.0)
.006-.012 (.15-.30)
.039 (1.0)
.008-.028 (.20-.71)
.039 (1.0)
.0012-.0026 (.030-.065)
Wear Limit
In. (mm)
3.2677-3.2684
(83.000-83.019)
.0007 (.019)
8.720 (221.5)
8.712 (221.3)
.006 (.15)
Page 25
In. (mm)
5.268-5.276 (133.81-134.01)
.004 (.10)
© 2005 Mitchell Repair Information Company, LLC.
1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
Valve Seat Contact Angle
Valve Guides
Valve Guide I.D.
Valve Guide Installed Height
(1)
Valve Stem-To-Guide Oil Clearance
Intake
Exhaust
Maximum Wear Limit
Cylinder Head-To-HLA Clearance
45°
.2366-.2374 (6.009-6.029)
.720-.744 (18.28-18.89)
.0010-.0024 (.025-.060)
.0012-.0026 (.030-.065)
.008 (.20)
.0010-.0071 (.025-.180)
(1)
Valve guide installed height is measured from top of installed guide to spring seat. See Fig. 6 .
VALVES & VALVE SPRINGS
Application
Valves
Face Angle
Contact Width
Installed Height
(1)
Normal
Serviceable
Minimum Margin
Intake
Exhaust
Minimum Refinish Length
Intake
Exhaust
Stem Diameter
Intake
Standard
Minimum
Exhaust
Standard
Minimum
Valve Springs
Free Length
Maximum Out-Of-Square
Compressed Length (Minimum)
1.8L DOHC
(1)
Specification In. (mm)
45°
.031-.055" (.79-1.40)
1.772-1.791" (45.00-45.50)
1.733-1.772" (45.60-46.50)
.035" (0.9)
.039" (1.0)
3.952" (100.39)
3.956" (100.49)
.2350-.2356" (5.970-5.985)
.2331" (5.920)
.2348-.2354" (5.965-5.980)
.2329" (5.952)
1.821" (46.26)
.064" (1.62)
1.555" (39.50)
(1)
Valve height is measured from top of installed valve to spring seat. See VALVE INSTALLED
HEIGHTS table under OVERHAUL. See Fig. 7 .
Microsoft
Sunday, July 05, 2009 1:23:06 PM Page 26 © 2005 Mitchell Repair Information Company, LLC.
CAMSHAFT
Application
End Play
Journal Diameter
Maximum Journal Out-Of-Round
Maximum Journal Runout
Journal Oil Clearance
Maximum Wear Limit
Lobe Height
Standard
Intake
Exhaust
Minimum
Intake
Exhaust
1994 Mazda MX-5 Miata
1994 ENGINES 1.8L 4-Cylinder
In. (mm)
.0032-.0120 (.081-.305)
1.0213-1.0222 (25.940-25.965)
.0015 (.038)
.0012 (.030)
.0014-.0032 (.035-.081)
.006 (.15)
1.7360 (44.094)
1.7560 (44.600)
1.7281 (43.894)
1.7480 (44.400)
Microsoft
Sunday, July 05, 2009 1:23:06 PM Page 27 © 2005 Mitchell Repair Information Company, LLC.

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Key features
- Engine identification
- Engine removal and installation
- Engine overhaul
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- Oil pump
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- Engine specifications